24-Hour Service Window
The 24-hour service window is the rolling 24-hour period that opens the moment a customer sends your business a message on WhatsApp. Inside this window you can reply with free-form "session" messages — plain text, images, buttons, lists, documents — without needing a pre-approved template and without paying WhatsApp per-message fees for those replies. It is one of the most important concepts on the WhatsApp Business API: it governs when you can speak freely, when you must switch to a template, and how you keep support conversations both compliant and cost-efficient.
In one line
The 24-hour service window is the free reply period that starts when a customer messages you. Inside it, you send free-form session messages; outside it, you must use an approved template, which is billed by category.What the 24-hour service window actually is
The 24-hour service window is a customer-service concept baked into how WhatsApp treats conversations. Whenever a person messages your WhatsApp Business number — a question, a keyword, a reply to your ad, a tap on a click-to-WhatsApp link — a 24-hour clock begins. For those 24 hours you are inside the service window and may respond with any free-form message: answers, order updates, images, PDFs, quick-reply buttons, or interactive lists. No template approval is required, and these service replies are not charged the way a business-initiated template is. Think of it as WhatsApp keeping a lane open for genuine, responsive customer service — as long as the customer started the conversation and you reply promptly.
How the window opens, resets, and closes
The single rule that trips up most teams is this: only the customer's inbound message opens or resets the window. Your replies keep the conversation warm but do not move the timer. Each new message the customer sends restarts the 24-hour countdown from that moment. When 24 hours pass with no new inbound message, the window closes and free-form messaging to that contact is switched off until they write again.
- Opens: the moment the customer sends any inbound message.
- Resets: every time the customer sends a new inbound message — the clock restarts from their latest one.
- Does not reset: your business replies, no matter how many you send.
- Closes: 24 hours after the customer's last inbound message.
- Re-opens: only when the customer messages you again.
Why it matters for cost and compliance
The window is where good WhatsApp economics and good compliance meet. Inside an open window your team can resolve a support case entirely with free-form session messages, so a fast, well-staffed inbox directly lowers how often you need to fall back on billable templates. Once the window closes, the only way to reach that customer is an approved template message, and every delivered template is billed by category — marketing, utility, or authentication each carry different prices. Since 1 July 2025, WhatsApp bills per delivered message by category rather than per conversation, so the window is best understood as a free service lane, not a billing unit. Respect the window and you stay both cheaper and firmly within WhatsApp's rules; ignore it and you either pay for templates you didn't need or, worse, try to force free-form messages that WhatsApp will simply reject.
- Inside the window: free-form service replies, no template needed.
- Outside the window: approved templates only, billed by category (ex-GST).
- Faster first response = more cases closed inside the free window.
- The window governs when you can reply free-form — it does not govern how you are billed.
Common mistakes teams make
Most 24-hour-window problems are process problems, not technical ones. Teams assume their own replies keep the window alive, batch support responses until the timer has already expired, or discover after the fact that a customer's message was answered a day late and now needs a template. Others send a marketing template to re-open a conversation and are surprised it carries a marketing charge. The fix is visibility and speed: know at a glance whether each conversation's window is open, close cases quickly while replies are free, and reach for the correct template category deliberately when a window has genuinely closed.
- Believing your outbound replies reset the timer — they don't.
- Letting the window lapse, then paying for a template you could have avoided.
- Sending a marketing template just to say 'we're back' — a utility template may fit and price differently.
- Not surfacing window status to agents, so replies land after the window has closed.
- Confusing the free service window with the old per-conversation billing model — billing is now per delivered message by category.
How InfiQ helps you work with the window
InfiQ is a WhatsApp-first CPaaS and official Meta Business Partner for Indian businesses, and its inbox is built around the service window rather than fighting it. Your agents see whether each conversation is inside an open 24-hour window, so they know instantly whether a free-form reply will go through or a template is required. Automations and quick replies help you respond fast enough to resolve cases while messaging is still free, and template management makes it clear which category — and which price — applies the moment a window has closed. It all runs on your own Business-Scoped User ID (BSUID) ownership with transparent ₹ pass-through pricing, so you keep control of both your WhatsApp presence and your costs.
- Live window status on every conversation, visible to every agent.
- Automations and canned replies to close cases inside the free window.
- Clear, category-aware template pricing when the window has closed.
- Full BSUID ownership and transparent ₹ pricing (ex-GST).
Frequently asked questions
What is the 24-hour service window on WhatsApp?+
Does my reply reset the 24-hour window?+
What happens when the 24-hour window closes?+
Are messages inside the 24-hour window free?+
Is the 24-hour window a billing unit?+
How do I extend or re-open the service window?+
What is the difference between a session message and a template message?+
Can automations reply inside the window?+
Turn fast replies into lower WhatsApp costs
See how InfiQ's shared inbox, live window-status tracking, and automations keep your team inside the free service window and cut needless template spend — book a demo today.